rifampin and Carcinoma

The pregnane X receptor (PXR) is the key regulator of our defense mechanism against foreign substances such as drugs, dietary nutrients, or environmental pollutants. Because of increased health consciousness, the use of dietary supplements has gradually increased, and most of them can activate PXR. Therefore, an analysis of the interaction between drugs and nutrients is important because altered levels of drug-metabolizing enzymes or transporters can remarkably affect the efficiency of a co-administered drug. In the present study, we analyzed the effect of vitamin K-mediated PXR activation on drug metabolism-related gene expression in intestine-derived LS180 cells via gene expression studies and western blotting analyses. We demonstrated that menaquinone 4 (MK-4), along with other vitamin Ks, including vitamin K

Topics: ATP Binding Cassette Transporter, Subfamily B; Carcinoma; Cell Line, Tumor; Cytochrome P-450 CYP3A; Gene Expression; Humans; Intestinal Neoplasms; Nutritional Physiological Phenomena; Pregnane X Receptor; Rifampin; Vitamin K; Vitamin K 1; Vitamin K 2

To further the development of a model for simultaneously assessing intestinal absorption and first-pass metabolism in vitro, Caco-2, LS180, T84, and fetal human small intestinal epithelial cells (fSIECs) were cultured on permeable inserts, and the integrity of cell monolayers, CYP3A4 activity, and the inducibility of enzymes and transporters involved in intestinal drug disposition were measured. Caco-2, T84, and fSIECs all formed tight junctions, as assessed by immunofluorescence microscopy for zonula occludens-1, which was well organized into circumscribing strands in T84, Caco-2, and fSIECs but was diffuse in LS180 cells. The transepithelial electrical resistance value for LS180 monolayers was lower than that for Caco-2, T84, and fSIECs. In addition, the apical-to-basolateral permeability of the paracellular marker Lucifer yellow across LS180 monolayers was greater than in fSIECs, T84, and Caco-2 monolayers. The transcellular marker propranolol exhibited similar permeability across all cells. With regard to metabolic capacity, T84 and LS180 cells showed comparable basal midazolam hydroxylation activity and was inducible by rifampin and 1α,25(OH)2D3 in LS180 cells, but only marginally so in T84 cells. The basal CYP3A4 activity of fSIECs and Caco-2 cells was much lower and not inducible. Interestingly, some of the drug transporters expressed in LS180 and Caco-2 cells were induced by either 1α,25(OH)2D3 or rifampin or both, but effects were limited in the other two cell lines. These results suggest that none of the cell lines tested fully replicated the drug disposition properties of the small intestine and that the search for an ideal screening tool must continue.

Topics: Biological Transport; Caco-2 Cells; Calcitriol; Carcinoma; Cell Line, Tumor; Cell Membrane Permeability; Colonic Neoplasms; Cytochrome P-450 CYP3A; Epithelial Cells; Humans; Intestinal Absorption; Intestine, Small; Pharmaceutical Preparations; Rifampin

Topics: Antitubercular Agents; Biopsy; Carcinoma; Combined Modality Therapy; Diagnosis, Differential; Ethambutol; Female; Humans; Isoniazid; Lymphatic Diseases; Middle Aged; Mycobacterium tuberculosis; Osteolysis; Osteomyelitis; Pleural Effusion; Pleural Neoplasms; Pyrazinamide; Rifampin; Sputum; Sternum; Tomography, X-Ray Computed; Tuberculosis, Osteoarticular

A 79-year-old man had a tumour under his jaw, due to tuberculosis in a lymph node following BCG treatment for carcinoma of the bladder.

Topics: Aged; BCG Vaccine; Carcinoma; Humans; Isoniazid; Lymph Nodes; Male; Rifampin; Treatment Outcome; Tuberculosis; Urinary Bladder Neoplasms

Topics: Adult; Carcinoma; Carcinoma, Small Cell; Humans; Lung Neoplasms; Male; Middle Aged; Rifampin; Tuberculosis, Pulmonary

The relationship between the methylation and processing of tRNA in both bacterial and mammalian cell systems was investigated by assessing the methylation of an existing population of precursor-tRNAs in the absence of tRNA synthesis. When the synthesis of tRNA in Escherichia coli B (rifampicin) and human KB cells (actinomycin D) was inhibited with the appropriate antibiotic, the incorporation of [3H[methyl groups into tRNA (via [methyl-3H]methionine labeling) rapidly declined with time and was essentially complete within 30 and 60 min, respectively. Although antibiotic treatment predictably reduced the incorporation of methyl groups into tRNA, it also resulted in significant changes in the distribution of the type of methylated products formed. Thus, for KB cells the marked increases in the per cent of radioactivity incorporated into 2'-0-methylribose derivatives, N2-methylguanine, and 3-methylcytosine of tRNA preparation pre-chased with actinomycin D for progressively longer periods of time prior to labeling with [methyl-3H]methionine led to the interpretation that these methylated constituents were formed predominantly during the late stages of tRNA maturation. Similarly, progessive and marked decreases in 1-, 7-, and N2, N2-methylguanine, and moderate decreases in 1-methyladenosine, 5-methylcytosine, and 5-methyluracil revealed that these methylated products were formed primarily during the early and intermediate stages of maturation, respectively. Similar analysis of E. coli B methylation products indicated that the bulk of methyl groups incorporated into the base moieties of tRNA (1- and 7-methylguanine, 2- and N6-methyladenine, and 5-methyluracil) occurred prior to the formation of 2'-0-methylribose derivatives. Additional evidence is presented which negates the possibility that an ancillary action of these antibiotics was the inhibition of specific tRNA-methyl-transferase enzymes.

Topics: Carcinoma; Cell Line; Dactinomycin; Escherichia coli; Humans; Methionine; Methylation; Mouth Neoplasms; Purines; Pyrimidines; Ribose; Rifampin; RNA, Transfer; Time Factors; tRNA Methyltransferases

Topics: Carcinoma; Cell Line; Cells, Cultured; Culture Media; Dactinomycin; Encephalitis Viruses, Tick-Borne; Humans; Immune Sera; Laryngeal Neoplasms; Rifampin; RNA, Viral; Viral Proteins; Virus Cultivation

Topics: Amphotericin B; Animals; Carcinoma; Cell Line; Cell Survival; Culture Media; Depression, Chemical; Dose-Response Relationship, Drug; Drug Synergism; HeLa Cells; Humans; L Cells; Leucine; Mice; Mouth Neoplasms; Polymyxins; Protein Biosynthesis; Rifampin; RNA, Neoplasm; Tetracycline; Tritium; Uridine

Topics: Animals; Aphthovirus; Carcinoma; Cell Line; Culture Techniques; Dactinomycin; Humans; Kidney; Laryngeal Neoplasms; Mitomycins; Poliovirus; Rifampin; Swine; Viral Plaque Assay; Virus Replication

Topics: Animals; Asparaginase; Bicarbonates; Carcinoma; Humans; Injections, Intraperitoneal; Leukemia Virus, Murine; Leukemia, Experimental; Mice; Rats; Rifampin; RNA Nucleotidyltransferases; Sodium; Virulence